ALTS was a study undertaken to find the best way to help women and their doctors decide what to do about the mildly abnormal and very common Pap test results known as ASCUS and LSIL. About three million women in the United States are diagnosed with ASCUS and LSIL each year. Organized and funded by the National Cancer Institute, ALTS included more than 5,000 women. It began in November 1996 and concluded at the end of 2000. Data analysis of the trial's findings is ongoing. ASCUS stands for atypical squamous cells of undetermined significance and LSIL for low-grade squamous intraepithelial lesions. Most of these mild abnormalities will go away without treatment, but some may signal a precancerous condition or, rarely, cancer. ALTS looked at three ways to manage these abnormalities: immediate colposcopy (magnified viewing and testing of the cervix) repeat Pap tests testing for human papillomavirus (HPV), an infection linked to cervical cancer